The present inventive concept herein relates generally to semiconductor integrated circuits, and more particularly to a voltage regulator having enhanced linearity in an operation region of high duty cycle.
Switching regulators are commonly used to provide power to devices such as RF power amplifiers which have a variable input voltage depending on output power. Typically, the input voltage of an RF power amplifier should be changed rapidly to reduce total power dissipation. In general, if the power consumption of a switching regulator is increased, its voltage transient response becomes fast, which is however unsuitable for mobile devices which are powered by limited power sources. Hysteretic regulators on the other hand are useful for operation with mobile devices because hysteretic regulators may realize low power consumption and fast voltage transient response in comparison with voltage-mode or current-mode switching regulators. However, a problem with hysteretic regulators is that a large output voltage ripple is produced in an operation region of high duty cycle, that is an operation region where a difference between an input voltage and an output voltage of the hysteretic regulator is small.